Output .tasty files in Pickler phase

Also simplify the logic to write the .tasty files.

Author: smarter

compiler/src/dotty/tools/backend/jvm/GenBCode.scala

@@ -218,11 +218,6 @@ class GenBCodePipeline(val entryPoints: List[Symbol], val int: DottyBackendInter
             val store = if (mirrorC ne null) mirrorC else plainC
             val tasty =
               if (!ctx.settings.YemitTastyInClass.value) {
-                val outTastyFile = getFileForClassfile(outF, store.name, ".tasty")
-                val outstream = new DataOutputStream(outTastyFile.bufferedOutput)
-                try outstream.write(binary)
-                finally outstream.close()
-
                 val uuid = new TastyHeaderUnpickler(binary).readHeader()
                 val lo = uuid.getMostSignificantBits
                 val hi = uuid.getLeastSignificantBits

compiler/src/dotty/tools/dotc/transform/Pickler.scala

@@ -13,6 +13,7 @@ import Symbols._
 import Flags.Module
 import reporting.ThrowingReporter
 import collection.mutable
+import NameOps._
 
 object Pickler {
   val name = "pickler"
@@ -67,6 +68,16 @@ class Pickler extends Phase {
       val pickled = pickler.assembleParts()
       unit.pickled += (cls -> pickled)
 
+      if (!ctx.settings.YemitTastyInClass.value) {
+        val parts = cls.fullName.stripModuleClassSuffix.mangledString.split('.')
+        val name = parts.last
+        val tastyDirectory = parts.init.foldLeft(ctx.settings.outputDir.value)((dir, part) => dir.subdirectoryNamed(part))
+        val tastyFile = tastyDirectory.fileNamed(s"${name}.tasty")
+        val tastyOutput = tastyFile.output
+        try tastyOutput.write(pickled)
+        finally tastyOutput.close()
+      }
+
       def rawBytes = // not needed right now, but useful to print raw format.
         pickled.iterator.grouped(10).toList.zipWithIndex.map {
           case (row, i) => s"${i}0: ${row.mkString(" ")}"